As the Internet protocol (Internet Protocol, IP) technologies spread, Ethernet is more and more widely used in the information and communications technology industry. External service data interfaces of network devices, such as a personal computer, various types of data switches, a server, a media processor, and a router widely use Ethernet interfaces with high generality but low cost. As Ethernet applications widely spread, Ethernet technologies are under constant development. The transmission rate of an Ethernet interface evolves from 10 Mbps to 100 Mbps, 1 Gbps, 10 Gbps, and 40 Gbps, and a 100 Gbps or even higher rate will appear in the future.
As the transmission rate of an Ethernet interface increases, the power consumption of each Ethernet interface constantly increases. For example, the power consumption of a 1 Gbps Ethernet interface increases by more than one time compared with that of a 100 Mbps Ethernet interface. A 1 Gbps Ethernet interface or a 100 Mbps Ethernet interface consumes a considerable amount of power even in an idle state.
Currently applied Ethernet interfaces generally support a multi-rate adaptive capability, for example, supporting a 100 M/100 M/10 M adaptive capability. During working, however, the highest rate mode supported by both parties is generally obtained after automatic negotiation through a rate self-negotiation mode. For example, the Ethernet interface of device A is a 1000 M/100 M adaptive interface, and the Ethernet interface of device B is a 1000 M/100 M/10 M adaptive interface. In this case, the interface transmission rate after negotiation by both parties is 1000 M. That is, even if interface traffic remains low for a long time, the Ethernet interfaces work at the negotiated highest rate, which increases the power consumption of the Ethernet interfaces.
At present, an energy-saving method is proposed in the Energy Efficient Ethernet standard 802.3az: When no data is transmitted, physical layers of two directly connected parties enter into a low power idle (Low Power Idle, LPI) mode to save energy. This mechanism yields favorable energy efficiency when the Ethernet interfaces are in the idle state where no data is transmitted for a long time. However, when the Ethernet interfaces continuously have low traffic, for example, the traffic remains at about 1% of the interface transmission rate, energy cannot be saved because the Ethernet interfaces cannot enter into the low-power LPI mode. As such, the manner for saving energy by entering into the LPI mode has restrictions, and cannot efficiently reduce the power consumption of Ethernet interfaces when data is transmitted between the Ethernet interfaces.
In addition to Ethernet interfaces, other communication interfaces, such as a PCIE (Peripheral Component Interconnect Express, peripheral component interconnect express) interface, an Ethernet SerDes (Serializers and Deserializers, serializers and deserializers) interface, and a wireless CPRI (Common Public Radio Interface, common public radio interface), also encounter the problem of large power consumption. If data is being transmitted on the communication interfaces, the power consumption of the communication interfaces cannot be reduced.